Lauric Acid Adsorption Using HСl-Enhanced Rice Husk Ash: A Path to Waste Frying Oil Purification

Plant-based calcium silicate from rice husk ash: A green adsorbent for free fatty acid recovery from waste frying oil

The decrease of fossil fuel resources and the awareness of the impact of greenhouse gases emissions on the environment have created a need to find alternative energy sources to replace traditional ones. Thus, recent years have seen the development of several sectors of renewable energy production with the government incentives. The production of biodiesel is an alternative of production of non-toxic, clean, renewable and biodegradable fuels. The aim of this work was to investigate the optimum conditions of the biodiesel production from waste frying oil in two-step catalyzed process and the optimization of methanol and acid concentration during its pretreatment. The oil had an acid value of 32.82 mg KOH/g. The first step, an acid was used as a catalyst for the esterification reaction to reduce the free fatty acid content in waste frying oil under 2% that was, with different dosages of the acid. The next base catalyzed transesterification processs converted the pretreated frying oil to biodiesel with the optimum combination. The highest yield of biodiesel after transesterification and purification process was 98% ester content with 0.214% of free fatty acid. The results showed that the acid catalystis a promising pretreatment to acidic oils or fats as they led to the production of an intermediary material with a low content of free fatty acid that can be directly used in the transesterification reaction for the production of biodiesel.

Synergistic association of elevated serum free fatty acid and glucose levels with large arterial stiffness in a general population: The Nagahama Study

In the cow a major characteristic of metabolic stress is an elevated level of plasma free fatty acid, due to increased lipid mobilization from adipose tissue. Elevated levels of free fatty acids in blood (complexed to albumin) are associated with increased lipotoxicity in non-adipose tissue. An overview is provided on the negative impact of free fatty acids and the metabolic stress imposed on the oocyte and early embryo and thus on bovine fertility. There is increasing evidence that in vitro as well as in vivo the elevated levels of free fatty acids in blood during metabolic stress can severely hamper oocyte and embryo development. However, fatty acids do also form an essential nutrient source for the oocyte and embryo, which indicates that these good and bad effects of fatty acids should be in subtle balance to optimize the developmental competence of the oocyte and embryo.

Methanol extracts of the hepatopancreas of mussels (Mytilus edulis) harvested at two locations (Ship Harbour and Wine Harbour) in eastern Nova Scotia, Canada, were found to be toxic to mice after intraperitoneal injection. The commonly known toxins, such as those associated with diarrhetic shellfish poison (DSP), paralytic shellfish poison, and domoic acid, were not present in the extracts. However, they were found to contain elevated levels of free fatty acids. Using a modified DSP extraction procedure the quantities of free fatty acids determined (by latroscan TLC/FID) in the hepatopancreases of mussels were 2.9 mg/g (Ship Harbour 1), 2.2 mg/g (Ship Harbour 2), 1.2 mg/g (Wine Harbour), and 0.15 mg/g (Prince Edward Island, control). After further investigation it was determined that certain unsaturated fatty acids were mainly responsible for the toxicity. These included palmitoleic, linoleic, linolenic, octadecatetraenoic, and eicosapentenoic acids. Artificial mixtures of pure standards of these acids prepared in the same concentrations as found in the shellfish samples were also toxic to mice. These results indicate that elevated levels of free fatty acids in mussel hepatopancreas from locations in eastern Canada can lead to mouse deaths when using the DSP mouse bioassay procedure.

We have evaluated the efficiency of sugar cane bagasse ash (SCBA), date palm seed carbon (DPSC), and rice husk ash (RHA) as natural adsorbents and compared them with the synthetic adsorbent Magnesol XL for improving the quality of waste frying oil (WFO) and for the impact on the physicochemical properties of the obtained biodiesel. We measured moisture content, refractive index (RI), density, acid value (AV), iodine value (IV), peroxide value (PV), and saponification value (SV), as well as fatty acid profile. Purification treatments with various levels of adsorbents caused significant (P ≤ 0.05) decreases in free fatty acids (FFAs), PVs, and IVs. The highest yields (86.45 and 87.80%) were observed for biodiesel samples produced from WFO treated with 2% Magnesol and 3% of RHA, respectively, followed by samples treated with 2 and 3% of DPSC or RHA. Pre-treatments caused a significant decrease in the content of C 18:2 linoleic acids, consistent with a significant increase in the content of monounsaturated and saturated fatty acids (MUFA) in the treated samples. The highest oxidation value (COX) (1.30) was observed for biodiesel samples produced from WFO without purification treatments. However, the lowest values (0.44–0.73) were observed for biodiesel samples produced from WFO treated with different levels of adsorbents. Our results indicate that pre-treatments with different levels of adsorbents regenerated the quality of WFO and improved the quality of the obtained biodiesel.

Hypothesis regarding the effects of gonadotropins on the level of free fatty acids and phospholipids in serum and follicular fluid during controlled ovarian stimulation

PurposeTo investigate serum levels of free fatty acids (FFAs) and their associations with routine serum lipids in diet-induced obese mice, which have been scantily reported before.MethodsMale C57BL/6 J mice were fed high-fat diets for 12 weeks to induce obesity. Levels of serum FFAs were measured by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry.ResultsObese mice had higher serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), but lower triglycerides (TG) than control mice. A total of 30 FFAs were found, and 3 saturated fatty acids (SFAs), all 8 monounsaturated fatty acids (MUFAs) and 7 polyunsaturated fatty acids (PUFAs) decreased in obese mice, but one SFA (C4:0) increased. Differences in the relative levels of individual FFAs to total FFAs, SFAs, MUFAs or PUFAs between obese and control mice were different from each other and from those evaluated by concrete levels except C4:0, C16:1, C19:1 and C18:4. Only the concrete levels of C4:0, C22:3 and C18:4 were associated with routine serum lipids, including C22:3 negatively with TG in control mice, and C4:0 and C18:4 positively with LDL-C in obese mice, although the relative levels of C4:0 to total MUFAs negatively with TC, and C23:3 to total SFAs or MUFAs negatively with TG in control mice. Different relative levels of the remaining FFAs were differently associated with different routine serum lipids in obese and/or control mice.ConclusionObesity may influence serum FFAs profiles. The relationship of individual FFAs and their relative levels to other FFAs with routine serum lipids in obese and control mice suggests that individual FFAs may interact with others and obesity on levels of routine serum lipids. Once confirmed, the interactions may be novel perspectives when fatty acids are used to improve hyperlipidemia in the subjects with obesity.

Spring canola (Brassica napus) seed grown in Ontario frequently exhibits elevated levels of free fatty acids (FFA) in the oil. The objective of this study was to determine the effects of various agronomic practices on FFA levels. Several field experiments were conducted in 1989 and 1990, and one experiment was conducted in 1987. FFA levels in the oil were higher in 1989 than in 1990. Two cultivars, Kristina and Global, were included in most experiments. The cultivar Kristina exhibited consistently lower FFA levels than the cultivar Global, averaging 42% less over years and treatments. Global averaged 1.31 and 0.62% FFA in 1989 and 1990, respectively. Decreasing seeding rates raised FFA levels in both cultivars in 1989 and in Global in 1990. Increasing rates of nitrogen (N) fertilizer increased FFA in Global in 1989. The removal of drought stress by irrigation during seed filling decreased FFA in Global by 46% in 1989. A combination of high N, low seeding rates, and no irrigation increased FFA in both cultivars in 1990. Delays in planting date resulted in higher FFA in 1987. The effect of these agronomic practices on yield and seed oil concentration were also reported. Applications of potassium or boron fertilizers did not affect FFA, nor did weekly applications of the fungicide, benomyl, or dosing plants with elevated levels of atmospheric ozone. The problem of elevated FFA can be diminished by avoiding excessively high nitrogen fertilizer rates and low seeding rates and by selection of low-FFA cultivars. Key words: Canola, free fatty acids, irrigation, ozone, planting date, oil content

The main objective of this study was to determine whether the excitotoxic cholinesterase inhibitor soman increases the catabolism of phospholipids in rat brain. Injections of soman (70 micrograms/kg, s.c.), at a dose that produced toxic effects, increased the levels of both free fatty acids (175-250% of control) and free choline (250% of control) in rat cerebrum 1 h after administration. All fatty acids contained in brain phosphatidylcholine were elevated significantly including palmitic (16:0), stearic (18:0), oleic (18:1), arachidonic (20:4), and docosahexaenoic (22:6) acids. The changes observed were consistent with those reported to occur following ischemia and the administration of other convulsants. Pretreatment of rats with the anticonvulsant diazepam (4 mg/kg, i.p.) prevented both the signs of soman toxicity and the soman-induced increase of choline and free fatty acids. Diazepam alone did not affect the levels of choline or free fatty acids, cholinesterase activity, or soman-induced cholinesterase inhibition, suggesting that soman toxicity involves a convulsant-mediated increase in phosphatidylcholine catabolism. In addition, administration of the convulsant bicuculline, at a dose that produces seizures and increases the levels of free fatty acids in brain, significantly increased the levels of choline. Results suggest that excitotoxic events enhance the hydrolysis of phosphatidylcholine in brain as evidenced by a concomitant increase in the levels of choline and free fatty acids.

Elevated levels of free fatty acids (FFAs) play a role in the pathogenesis of insulin resistance and atherosclerosis. Adipose triglyceride lipase (also defined as patatin-like phospholipase domain containing 2 or PNPLA2) has been demonstrated to contribute to the release of FFA. The aim of this study was to investigate the association of PNPLA2 gene variations with FFA levels in healthy Chinese Han population. Single-nucleotide polymorphisms of PNPLA2 were genotyped using TaqMan method to perform association studies with serum level of FFA and other lipid parameters in 1765 subjects among healthy Chinese Han population. All the subjects were divided into two groups: normal FFAs group (FFAs ≤0.88 mmol/L) and high FFAs group (FFAs >0.88 mmol/L). Neither rs7925131 nor rs7942159 was significantly associated with FFA level. We observed no difference in the genotype frequency of rs7925131 or rs7942159 between the normal FFA group and the high FFA group. Our results do not support an association of rs7925131 or rs7942159 with the FFA levels among the Chinese Han population.

The ability of insulin to suppress gluconeogenesis in type II diabetes mellitus is impaired; however, the cellular mechanisms for this insulin resistance remain poorly understood. To address this question, we generated transgenic (TG) mice overexpressing the phosphoenolpyruvate carboxykinase (PEPCK) gene under control of its own promoter. TG mice had increased basal hepatic glucose production (HGP), but normal levels of plasma free fatty acids (FFAs) and whole-body glucose disposal during a hyperinsulinemic-euglycemic clamp compared with wild-type controls. The steady-state levels of PEPCK and glucose-6-phosphatase mRNAs were elevated in livers of TG mice and were resistant to down-regulation by insulin. Conversely, GLUT2 and glucokinase mRNA levels were appropriately regulated by insulin, suggesting that insulin resistance is selective to gluconeogenic gene expression. Insulin-stimulated phosphorylation of the insulin receptor, insulin receptor substrate (IRS)-1, and associated phosphatidylinositol 3-kinase were normal in TG mice, whereas IRS-2 protein and phosphorylation were down-regulated compared with control mice. These results establish that a modest (2-fold) increase in PEPCK gene expression in vivo is sufficient to increase HGP without affecting FFA concentrations. Furthermore, these results demonstrate that PEPCK overexpression results in a metabolic pattern that increases glucose-6-phosphatase mRNA and results in a selective decrease in IRS-2 protein, decreased phosphatidylinositol 3-kinase activity, and reduced ability of insulin to suppress gluconeogenic gene expression. However, acute suppression of HGP and glycolytic gene expression remained intact, suggesting that FFA and/or IRS-1 signaling, in addition to reduced IRS-2, plays an important role in downstream insulin signal transduction pathways involved in control of gluconeogenesis and progression to type II diabetes mellitus.

Adrenergic effects on plasma levels of glucagon, insulin, glucose and free fatty acids were studied in fasted rabbits by infusing epinephrine, norepinephrine, isoproterenol, phentolamine (an adrenergic alpha-receptor blocking drug) and propranolol (an adrenergic beta-receptor blocking drug). The adrenergic effects on the plasma levels of insulin, glucose and free fatty acids were similar to those found in other species. The plasma levels of insulin were increased by beta-receptor stimulation (isoproterenol, phentolamine + epinephrine) and decreased by alpha-receptor stimulation (epinephrine, norepinephrine, propranolol + epinephrine). The plasma levels of glucose were increased by both alpha- and beta-receptor stimulation, and the epinephrine-induced hyperglycaemia was only blocked by combined infusions with phentolamine and propranolol. The plasma levels of free fatty acids were increased by saline and further increased by beta-receptor stimulation (isoproterenol), while epinephrine and norepinephrine gave variable results. Alpha-receptor stimulation (propranolol + epinephrine) slightly decreased the plasma levels of free fatty acids. The plasma levels of glucagon, however, were mainly increased by alpha-receptor stimulation (epinephrine, norepinephrine, propranolol + epinephrine) and increased only to a minor extent by beta-receptor stimulation (isoproterenol, phentolamine + epinephrine) in rabbits. This is in contrast to results reported for humans, where beta-receptor stimulation seems to be most important in stimulating glucagon release.

Brain free fatty acids (FFA) and diacylglycerols (DG) are maintained in a dynamic equilibrium with the membrane phospholipids. Many factors, including ischemia and drug induced convulsion, are known to disturb the equilibrium resulting in alteration of the FFA and DG level. The biochemical mechanism responsible for the disturbances is not yet fully understood. In this study, the FFA and DG in brain due to carbamylcholine and pentylenetetrazol induced convulsion and the suppressive action by scopolamine and diazepam was investigated. Carbamylcholine injected into rat brain intracerebrally gave rise to clonic and tonic seizures as well as exhibited some of the cholinergic symptoms. An increase in FFA and DG level was observed. The increase in FFA (but not DG) was blocked by pretreatment of scopolamine. Scopolamine injection (i. p.) alone could reduce the FFA level in brain but not DG. In all cases, subjecting the brain to 2 min post-decapitative ischemia resulted in a large increase in FFA and DG. Carbamylcholine stimulation potentiated the ischemia-induced increase in FFA and DG. Under this type of stimulation, arachidonic and stearic acids were preferentially released during stimulation and ischemia. Seizure was observed within two min after pentylenetetrazol administration (i. p.) to young rats. This drug also induced an increase in brain FFA but apparently was not effective in modulating the DG level. Pretreatment of rats with diazepam could effectively reduce the pentylenetetrazol-induced convulsion and FFA increase. A decrease in both FFA and DG was observed when rats were treated with diazepam (i. p.) alone. In general, FFA level in brain is increased during stimulation and decreased during depression. The differences in the FFA and DG changes as shown by convulsive and anti-convulsive agents further suggest that multiple biochemical mechanisms are present in mediating these changes.

Effects of an acute increase in plasma triglyceride levels on glucose metabolism in man